500 km is the initial running-in, the speed is generally below 70-80 km, and the rotation speed is not more than 2200 rpm; 500- 1000 km is the medium-term running-in, and the rotating speed is generally 90- 100 km, and the rotating speed is below 2500 rpm; 1000- 1500 km is the late running-in, and the rotation speed is below 120 km, and the rotation speed does not exceed 3000 rpm.